Retractable support member

ABSTRACT

A reproducing apparatus includes an illuminating station and a system for forming an image on a sheet of support material of an object positioned at the illuminating station. The viewing station includes a transparent viewing platen having a registration edge against which the object is placed for imaging. A support member is arranged adjacent to the registration edge of the platen. Apparatus is provided for supporting the member in a first position above the level of the platen, and for supporting the member for movement to a second position downwardly of the first position in response to the urging of an object placed on the viewing platen.

CROSS REFERENCE TO RELATED APPLICATIONS

U.S. application Ser. No. 811,735, filed June 30, 1977, to Taylor etal., for an Improved Document Handling Apparatus and ReproducingMachine; U.S. application Ser. No. 811,736, filed June 30, 1977, toTaylor et al., for a Vernier Belt Tensioning System; U.S. applicationSer. No. 818,781, filed July 25, 1977, to Hacknauer, for a DocumentDecelerator and Stacker; and U.S. application Ser. No. 822,667, filedAug. 4, 1977, to Taylor et al., for a Counter Balancing Apparatus.

BACKGROUND OF THE INVENTION

This invention relates to a retractable support member arranged for useadjacent a book copying edge of a reproducing machine. The retractablesupport member is particularly adapted for use in conjunction with adocument handling system of the reproducing machine for supportingdecelerating members or document trays adjacent the exit of the documenthandling system.

PRIOR ART STATEMENT

A variety of reproducing machines are known which incorporate so-calledbook copying edges. Conventionally, these reproducing machines employ atransparent viewing platen held in a generally horizontal plane. Oneside or edge of the platen is used to register objects on the platen forviewing by the imaging system. In order to facilitate the copying ofbooks without bending or breaking their bindings, the portion of thecopier adjacent the registration edge of the platen is generally slopeddownwardly. This allows the book to be opened so that the pages arespread apart less than 180° thereby reducing any damage to the bookbinding. The Xerox 3100 and 4000 copiers are exemplary of machineshaving such book copying arrangements.

It is also well known as will be described in detail hereafter, toemploy document handling systems which are arranged to advance adocument on and/or off the viewing platen. In many instances thedocuments are advanced into a receiving tray which is arranged closelyadjacent to the book copying edge. In U.S. Pat. Nos. 3,888,584 to Smith,and 3,901,594 to Robertson, a document holding tray and a document catchtray are arranged adjacent the book copying edge of a reproducingmachine, which further includes a document handling system for ejectingdocuments from the platen into the catch tray. The document support trayis arranged above the level of the platen and the document catch tray isarranged below the level of the platen. When one attempts to place abook on the platen and utilize the book copying edge thereof, thedocument holding tray is in the way. Means are provided in accordancewith the teachings of the patentees for swinging the document holdingtray upwardly out of the way of the book to gain access to the bookcopying edge.

In the systems as described in these patents, however, it is necessaryfor the operator to manually swing the tray out of the way beforeplacing the book on the platen and to then manually swing the tray backinto its operative position if ordinary sheet type copying is desired.

It is desired in accordance with the present invention to avoid thismanual intervention of the operator necessitated by the prior artapproach of providing a pivotally supported tray, which must be movedout of the way to do book copying, and to substitute in its place asystem whereby a support member normally positioned above the level of aplaten is automatically retracted responsive to the urging of the objectto be imaged.

Other reproducing machines currently commercially available employdocument handling systems for advancing documents both on and off theviewing station of the machine. These document handling systemspresently in use may be classified as semi-automatic when the documentsare individually manually inserted into the document handler which thenfeeds them on and off the viewing platen. In some machines fullyautomatic document handling systems are employed wherein the documentsare automatically separated from a stack thereof and serially fed to theplaten. In some cases provision has been made to recirculate thedocuments so that they may be serially fed on and off the platen adesired number of times to form a desired number of sets.

The present invention is particularly adapted for use with documenthandling systems which employ a single stretch-type document handlingbelt as the platen transport. Such document handling systems areexemplified by the following U.S. Pat. Nos. 3,565,420, to Howard,3,889,943 to Krayer, and 3,941,376 to Liechty. In each of these patentsa single wide document transport belt is utilized to advance a documenton and off the viewing platen of the reproducing machine in a fullyautomatic or recirculating fashion. The document transport belt issupported about first and second pulleys. This approach is usedcommercially in the Xerox 9200 duplicator.

U.S. Pat. Nos. 3,844,552 to Bleau, 3,908,986 to Bleau, 3,910,570 toBleau, are illustrative of semi-automatic type document handlingsystems. Such systems include a pre-registration station into which theoperator manually places a document which is either manually registeredagainst a stop or automatically registered against the stop as in theBleau '986 patent. U.S. Pat. No. 3,936,041 to Shiina, et al. isillustrative of a fully automatic document handling system whereindocuments are separated from a stack and then advanced on and off theplaten all automatically without operator intervention. These patentsare also of interest for their disclosures with respect to belttransport type document handling systems.

In addition to the aforenoted patents, the following disclosures arebelieved to be of interest with respect to document handling systems ofthe type contemplated in accordance with this invention. IBM TechnicalDisclosure Bulletin, Vol. 19, No. 5, October 1976, pages 1589 to 1591,discloses a semi-automatic document handling system control arrangementemploying multiple sensors. IBM Technical Disclosure Bulletin, Vol. 17,No. 4, September 1974, page 1131, discloses a platen registration gatemechanism. IBM Technical Disclosure Bulletin, Vol. 17, No. 4, September1974, page 1135, discloses an output tray stacking system. The outputtray stacker includes a wire guide for decelerating documents enteringthe tray.

SUMMARY OF THE INVENTION

In accordance with the present invention a reproducing apparatus isprovided which includes a illuminating station and means for forming animage on a sheet of support material of an object positioned at theilluminating station. The viewing station includes a transparent viewingplaten having a registration edge against which the object is placed forimaging. A member is arranged adjacent the registration edge of theplaten. In accordance with this invention means are provided forsupporting the member in a first position above the level of the platenand for supporting the member for movement to a second positiondownwardly of the first position in response to the urging of an objectplaced on the viewing platen.

In accordance with a preferred embodiment, the member comprises asupport member arranged at the discharge end of a document handlingsystem supported about the platen. The support member can be used tosupport document decelerators for decelerating documents ejected by thedocument handling system into a document catch tray. The support memberin the position above the level of the platen is arranged above thedocuments as they are ejected into the catch tray so that they can beurged downwardly while being decelerated.

Optionally, if desired, the support member can be used in addition oralternatively to support a document holding tray or other operator workspace providing means.

Book copying is easily accomplished in accordance with this inventionwithout operator intervention to remove the support member or tray whichwould otherwise block access to the registration or book copying edge ofthe copier. As a book is placed on the platen the side of the book whichis not being imaged intercepts the support member or tray andautomatically deflects it to its lowered position thereby providingaccess to the book copying edge.

Accordingly, it is an object of this invention to provide an improvedreproducing apparatus.

It is a further object of this invention to provide an apparatus asabove including a member arranged adjacent the registration edge of aviewing platen and means for supporting the member for movement to alowered position at the urging of an object placed on the platen.

It is a still further object of this invention to provide an improvedapparatus as above further including a document handling systemassociated with said member.

These and other objects will become apparent from the followingdescription and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a reproducing apparatusincluding a document handling system in accordance with this invention.

FIG. 2 is a partial top view of the document handling system of FIG. 1with the cover removed.

FIG. 3 is a partial sectional view of the input transport and waitstation of the document handling apparatus.

FIG. 4 is a partially cut-away perspective view of the platen belttransport of the document handling apparatus.

FIG. 5 is a partial cross-sectional view of the output transport andplaten registration mechanism of the document handling apparatus.

FIG. 6 is a partial sectional view of the input transport and waitstation of FIG. 3 at a different stage of its operation.

FIG. 7 is a partial bottom view of the document handling apparatus.

FIG. 8 is an exploded view of the adjustable side frames and driverollers of the platen belt transport.

FIG. 9 is a partial side view of the front adjustable side frame of theplaten belt transport.

FIG. 10 is a partial side view of the rear adjustable side frame of theplaten belt transport.

FIG. 11 is a partial top view of the platen registration mechanism.

FIG. 12 is a partial cross-sectional view of the output transport andplaten registration mechanism of FIG. 5 at a different stage of itsoperation.

FIG. 13 is a rear view in partial cross-section showing operation of theplaten cover counterbalance mechanism and the retractable manualregistration guide.

FIG. 14 is a partial top view showing the retractable manualregistration guide.

FIG. 15 is a partial cross-sectional view of the output tray anddocument decelerator associated with the document handling apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1 there is shown by way of example an automaticxerographic reproducing machine 10 which includes a document handlingapparatus 11 of the present invention. The reproducing machine 10depicted in FIG. 1 illustrates the various components utilized thereinfor producing copies from an original. Although the apparatus 11 of thepresent invention is particularly well adapted for use in an automaticxerographic reproducing machine 10, it should become evident from thefollowing description that it is equally well suited for use in a widevariety of processing systems including other electrostatographicsystems and it is not necessarily limited in its application to theparticular embodiment or embodiments shown herein.

The reproducing machine 10 illustrated in FIG. 1 employs an imagerecording drum-like member 12, the outer periphery of which is coatedwith a suitable photoconductive material 13. One type of suitablephotoconductive material is disclosed in U.S. Pat. No. 2,970,906, issuedto Bixby in 1961. The drum 12 is suitably journaled for rotation withina machine frame (not shown) by means of shaft 14 and rotates in thedirection indicated by arrow 15 to bring the image-bearing surface 13thereon past a plurality of xerographic processing stations. Suitabledrive means (not shown) are provided to power and coordinate the motionof the various cooperating machine components whereby a faithfulreproduction of the original input scene information is recorded upon asheet of final support material 16 such as paper or the like.

The practice of xerography is well known in the art and is the subjectof numerous patents and texts including Electrophotography by Schaffert,and Xerography and Related Processes by Dessauer and Clark, bothpublished in 1965 by the Focal Press.

Initially, the drum 12 moves the photoconductive surface 13 through acharging station 17. In the charging station 17, an electrostatic chargeis placed uniformly over the photoconductive surface 13 preparatory toimaging. The charging may be provided by a corona generating device ofthe type described in U.S. Pat. No. 2,836,726, issued to Vyverberg in1958.

Thereafter, the drum 12 is rotated to exposure station 18 wherein thecharged photoconductive surface 13 is exposed to a light image of theoriginal input scene information whereby the charge is selectivelydissipated in the light exposed regions to record the original inputscene in the form of a latent electrostatic image. A suitable exposuresystem may be of a type described in U.S. Pat. No. 3,832,057, issued toShogren in 1974. After exposure drum 12 rotates the electrostatic latentimage recorded on the photoconductive surface 13 to development station19 wherein a conventional developer mix is applied to thephotoconductive surface 13 of the drum 12 rendering the latent imagevisible. A suitable development station is disclosed in U.S. Pat. No.3,707,947, issued to Reichart in 1973. That patent describes a magneticbrush development system utilizing a magnetizable developer mix havingcoarse ferromagnetic carrier granules and toner colorant particles. Thedeveloper mix is brought through a directional flux field to form abrush thereof. The electrostatic latent image recorded on thephotoconductive surface 13 is developed by bringing the brush ofdeveloper mix into contact therewith.

Sheets 16 of final support material are supported in a stack arrangementof an elevating stack support tray 20 or in an auxiliary tray 21. Sheetseparators 22 and 23 selectively feed individual sheets from theirrespective stacks to a registration system which includes rolls 24 and25. The sheet is then forwarded to the transfer station 26 in properregistration with the image on the drum. The developed image on thephotoconductive surface 13 is brought into contact with the sheet 16 offinal support material within the transfer station 26 and the tonerimage is transferred from the photoconductive surface 13 to thecontacting side of the final support sheet 16. The final supportmaterial may be paper, plastic, etc., as desired.

After the toner image has been transferred to the sheet of final supportmaterial 16 the sheet with the image thereon is advanced to a suitablefuser 27 which coalesces the transferred powder image thereto. One typeof suitable fuser is described in U.S. Pat. No. 2,701,765, issued toCodichini, et al. in 1955. After the fusing process the sheet 16 isadvanced selectively to a suitable output device such as tray 28 orsorter 29.

Although a preponderance of the toner powder is transferred to the finalsupport material 16, invariably some residual toner remains on thephotoconductive surface 13 after the transfer of the toner powder imageto the final support material. The residual toner particles remaining onthe photoconductive surface 13 after the transfer operation are removedfrom the drum 12 as it moves through a cleaning station C. The tonerparticles may be mechanically cleaned from the photoconductive surface13 by any conventional means as, for example, the use of a blade as setforth in U.S. Pat. No. 3,740,789, issued to Ticknor in 1973.

A document handling system 11 of this invention is used to advancedocuments on and off a viewing platen P where they are scanned by theoptical system 18.

It is believed that the foregoing description is sufficient for purposesof the present application to illustrate the general operation of anautomatic xerographic copier 10 which can embody the apparatus 11 inaccordance with the present invention.

Referring now to FIGS. 1 through 5, the basic elements of the documenthandling system 11, in accordance with the present invention, will bedescribed along with their operation. The document handler 11 includesan input transport 30 comprised of input pinch rolls 31 and 32, whichare selectively disengageable so that a document may be readily placedbetween them. The input transport 30 also includes a wait station 33 forpre-registering the document. The wait station 33 is comprised of apivotally supported registration gate 34 and a pivotally supported upperchute 35. The gate 34, chute 35, and pinch rolls 31 and 32 areinter-connected so that when the gate is up in a sheet 16 blockingposition, the pinch rolls are separated. As the gate 34 drops out ofsheet blocking position the pinch rolls come together to advance thedocument into the next station which comprises the belt-type platentransport 40.

A suitable static eliminating device 36 is arranged between the inputtransport 30 and the platen belt transport 40. In the embodiment shownin FIG. 3, the static eliminator 36 is comprised of a pin-type coronagenerating device wherein a plurality of pins are spaced transversely tothe direction in which the document is moving. The corona generator isarranged to spray the document with an appropriate AC corona toneutralize or discharge any static build-up on the document before itenters the platen transport 40. While it is unusual to place the staticeliminating device 36 before the platen belt transport 40, it has beenfound effective at such a location for reducing the static build-up onthe belt and for providing adequate stacking of documents in the outputtray 41. For the sake of simplicity the static eliminator 36 is shownsolely in FIG. 3, and has been removed from the other views of theapparatus 11 in order to reveal other components.

Referring to FIGS. 1 through 5, the platen belt transport 40 iscomprised of a single wide belt 42 having one run 43 over the platen P.This is desirable to avoid the print-out of the belt on the resultingcopy sheet. The belt 42 is normally formed of a stretch-type materialwhich is white in color so as to reduce the occurrence of a black borderprint-out on the copies. The belt 42 is wrapped about two pulleys 44 and45, which are arranged so that the belt surface at the bottom of apulley is slightly above the surface of the platen, perhaps by about0.030 inches. The sag of the belt 42 is sufficient so that the beltengages the platen. The drive force which the belt 42 imparts to thedocument is controlled by means of back-up rolls 46 and 47, supportedinternally of the belt.

The input back-up roll 46 is arranged close to the input drive pulley44, and controls the normal force applied by the belt 42 to the documentas it is driven onto the platen P. A platen registration gate 50 isprovided at the far end of the platen P. The document is driven by thebelt 42 against the gate 50 in order to properly position the documenton the platen P for imaging. During the imaging cycle the registrationgate 50 is retracted. After imaging the document is advanced off theplaten P by means of the belt transport 40 and a set of output pinchrolls 55. The output pinch rolls corrugate the document to increase itsbeam strength so that it will properly stack in the output tray 41 ofthe document handling system 11. Document decelerators 56 associatedwith the output tray 41 act upon the document as it enters the outputtray to properly stack it therein.

The document handling system is actuated by a number of sensors as inFIG. 2. A lever actuated switch 60 is positioned just ahead of the nipof the input transport rolls 31 and 32 and serves to condition themachine for operation in a document handling mode. A second sensor 61,which preferably comprises a photocell, is arranged to sense propercorner registration of the document at the wait station 33. A thirdsensor 62 also preferably comprising a photocell is used to detect thatthe document has been advanced off the platen P. The third sensor isarranged just prior to the output pinch rolls 55.

In operation the document handling system 11 is activated by inserting adocument into the wait station 33. This actuates the mode switch 60which in turn activates the input sensor 61 and signals the logic (notshown) of the machine that a "DHS" copy is desired. When the corner ofthe document interrupts the input registration sensor 61, aready-to-feed light is lit, and the system is assured that the originalhas been inserted within a predetermined skew and side shift tolerance.The logic then provides a 0.4 second delay after the start-print buttonis pressed, or after a second document is inserted when in a chain feedmode. This allows the operator time to let go of the document before itis advanced onto the platen P.

As the wait station 33 fingers 34 retract, the pivoting upper chute 35is raised which increases the clearance for bulky originals. At the sametime the input rolls 31 and 32 pinch is made. A short time later aclutch 65, as in FIG. 13, is actuated and the drives 66 are started. Thedocument is driven onto the platen P by the input rolls 31 and 32 and bythe input back-up roll 46 of the belt transport 40.

In the event that a document does not uncover the input sensor 61, a jamis signaled. At an appropriate time the register edge 51 is raised fromits normally retracted position. This also raises the registrationback-up roll 47 as well. The document is driven against the registeredge 51 by the document belt alone, removing any skew by coastover-drive. The register edge 51 is lowered during scan of the exposuresystem 18.

When scan is complete the drives 66 start again. If a second documenthas been properly inserted into the wait station 33 during scan, thisdocument will be transported onto the platen P at the same time thefirst document is fed off. If the second original has not been insertedsoon enough to allow the wait station 33 to be actuated, it will be heldup at the wait station until the first document is driven off the platenP.

The registration back-up roll 47 provides the necessary normal force todrive the first document off the platen P. If this document does notreach the exit sensor 62 within an alloted time, the logic signals ajam. The exiting document is fed into the exit tray 41 by the outputrolls 55 which corrugate it to provide the beam strength needed to stackeasily. Failure to leave the exit sensor 62 at the end of a cyclesignals a jam.

Having thus described the general features of the document handlingsystem 11 of this invention and its general mode of operation, furtherdetail will now be given for the various sub-assemblies and sub-systemswhich make up the document handler.

WAIT STATION AND INPUT TRANSPORT

Referring now to FIGS. 2, 3, 6, and 7, the wait station and inputtransport will be described in greater detail. The wait station 33 andinput transport 31 and 32 are supported by a structurally rigid castingor frame member 70 which is connected to the optical frame (not shown)in such a manner as to align the wait station 33 with the optical system18 to ensure that the input transport 31 and 32 advances the documentproperly onto the platen P without skew or misregistration. The inputtransport is comprised of a set of pinch rolls 31 and 32. The fourspaced apart upper rolls 31 are mounted to the input roll drive shaft 71and are used to drivingly engage the document for advancement onto theplaten P. The lower input pinch rolls 32 are supported in cantileverfashion by spring members 72 secured to the input frame member 70. Twoof the lower input pinch rollers 32 are rotatably supported to idle upona first shaft 73, and the other two are rotatably supported to idle upona separate second shaft 74. This helps to provide a uniform normal forcebetween the pinch rollers when they are engaged. The near side lowerinput pinch roller 32 includes a reduced diameter shoulder 75 so that itwill not engage the very end of an 81/2 × 11 inch sheet. This reducesthe propensity for skewing such sheets.

The pre-registration gate member 34 includes spaced apart registrationstop fingers 80. It is pivotally supported below the input station framemember 70 upon shaft 81 so that the fingers 80 project through openings82 in the frame member. Initially the registration fingers 80 aresupported as in FIG. 3 in raised position so as to block a document fromentering the nip between the transport belt 42 and the platen P.

The upper registration chute 35 is also arranged to be pivoted about ashaft 83. When the registration fingers 80 are in their operative, orraised position, the upper registration chute 35 is in its loweredposition as in FIG. 3. The upper registration chute 35 serves to limitthe thickness of a document which can be inserted into the wait station33 as well as serving to prevent documents from jumping thepre-registration gate 34. The upper chute 35 is biased in acounterclockwise direction about its pivot axis by gravity. Should adocument remain lodged over the pre-registration gate fingers 80 whenthe gate is raised, the document will not be punctured since the upperchute 35 merely pivots upwardly.

The upper chute 35 includes an arm 85 as in FIGS. 2, 3, and 6 having anadjustable set screw 86 therein. A plate-type actuating member 87 as inFIG. 7 is supported by the pre-registration gate 34 pivot shaft 81 andincludes a tab 88 for engaging the set screw 86 connected to the upperregistration chute 35. At the opposing end of this actuating member 87,a solenoid 90 is connected. In the operative position, as in FIG. 3, aset screw 91 in the input station frame 70 is used to limit the heightto which the registration gate fingers 80 extend above the upper surfaceof the frame.

The positional arrangement shown in FIG. 3 comprises the operativeposition for pre-registering a document at the wait station 33. In thisposition the solenoid 90 is not actuated and a spring 92 biases theregistration gate pivot shaft 81 so that the gate is normally in itsraised position. The rear portion of the registration gate member 34includes a plurality of tabs 93 as shown in FIG. 7 which engage the topsof the lower input roll shafts 73 and 74 at their ends so that when thefingers 80 are raised the tabs 93 deflect the lower pivot rolls 32 toseparate them from the upper pinch rolls 31. This allows a sheet to beeasily placed between the pinch rolls 31 and 32 and registered againstthe fingers 81.

To initiate the document handling mode of operation, a document isplaced into the wait station 30 and up against the pre-registrationfingers 80. The document is also registered against the input top coverregistration strip 100 as in FIG. 2, to provide corner registrationwhich is sensed by the input sensor 61.

After a suitable time delay the solenoid 90 is actuated to lower theinput registration fingers 80 out of sheet blocking relationship as inFIG. 6. Since the registration member 34 has pivoted about its axis itstabs 93 no longer deflect the shafts 73 and 74 of the lower input rolls30 so that the pinch of the input rolls 31 and 32 is closed to advancethe document sandwiched therebetween into the belt transport station 40.The actuating member 87 connected to the registration member pivot shaft81 operates upon the set screw 86 of the upper chute 35 to pivot itclockwise in order to widen the throat between it and the surface of theinput frame casting 70. This serves to reduce the drag on the sheet asit is fed onto the platen. The upper chute 35 may be manually pivotedopen even wider as shown in phantom to facilitate jam clearance.Therefore, upon actuation of the input station 30 solenoid 90, thefingers 80 are lowered, the upper chute 35 is raised, and the pinch ofthe input rolls 31 and 32 is closed to advance the document into thenext station of the document handling system 11 which comprises theplaten belt transport 40.

PLATEN BELT TRANSPORT SYSTEM

Referring now to FIGS. 2, 4, 5, 8, 9, 10, 11, and 12, the platen belttransport 40 will be described in greater detail. The platen belttransport 40 is supported within a frame assembly 105 comprised of front106 and rear 107 adjustable side frame members, and input 108 and exit109 end frame members. The frame assembly 105 is pivotally supported atthe input station 30 about the input pinch roller drive shaft 71 bybeing suitably journaled thereabout.

The platen belt transport 40 is comprised of a single wide stretch-typebelt which is arranged about the input drive pulley 44 and an exit idlerpulley 45. Both the input and exit pulleys 44 and 45 are journaled forrotation in the front and rear adjustable side frames 106 and 107.Internally of the belt 42, an input back-up roll 46 is pivotallysupported by means of a pan-like frame member 110. The input back-uproll 46 is rotatably arranged at one end of the frame 110 member and theother end thereof is pivotally supported about a shaft 111 securedbetween the front and rear adjustable side frames 106 and 107 of theplaten belt transport 40. A second pivotally supported pan-like framemember 115 is pivotally arranged at one end about the shaft 111 androtatably supports the registration back-up roll 47 at its free end.

The frame member 110 supporting the input back-up roll 46 is shorterthan the frame member 115 supporting the output back-up roll. Theback-up rolls 46 and 47 are urged against the back of the belt 42 bytheir weight and the weight of their associated frame member 110 or 115.The normal force exerted by these rolls 46 and 47 against the belt 42 isimportant for obtaining the desired driving force between the belt andthe document during advancement of the document. In order to provide thedesired level of drive force, weights 116 and 117 are supported by therespective input and registration back-up roll frame members 110 and115. Therefore, the normal force exerted by the back-up rolls 46 and 47can be regulated by the size of the weights 116 and 117 and theirpositions on their respective pans 110 and 115.

It has been found that the platen P surface is not absolutely flat andthat a variation occurs in the force with which the input back-up roll46 urges the belt against the platen from the front to the back side ofthe platen. This can result in a significant loss in latitude for thesetting of the input back-up roll normal force. Therefore, in accordancewith one feature of the document handling system 11 herein, the inputback-up roll is formed so that it includes two doughnut-shaped portions120 or sections of enlarged diameter as in FIG. 4. These back-up rollsections 120 of enlarged diameter insure that the input back-up roll 46applies a uniform pressure at the two points where it engages the platenbelt 42 even if the platen P is not absolutely flat. This reduces thetendency for skewed feeding of the document onto the platen P. Theaforenoted input back-up roll 46 construction results in a substantialimprovement in the latitude of the platen belt transport reducing itssensitivity to the belt 42 tension and the height of the input drivepulley 44.

Cone-shaped members 121 rotatably supported about stub shafts mounted tothe front and rear side frames 106 and 107 of the belt transport 40 areemployed to insure that the belt properly tracks about the input andoutput pulleys 44 and 45. The long pan 115 is sufficiently flexible toinsure adequate conformity of the registration back-up roll 47 acrossthe platen. The front pan 110 is too short to assure such conformity,and, therefore, a slot 122 is provided in that pan. This slot 122 allowsthe pan to move about the pivot shaft 111 to insure conformity betweenthe raised portions 120 of the roll 46 and the platen P, even if theplaten is warped. The raised portions 120 of the input back-up roll 46are arranged toward the rear of the document handler 11 so that it canproperly handle shorter documents.

In order to balance the input back-up roll 46 loading the normal forceassisting weights 116 is arranged toward the front side of the pan 110,thereby uniformly loading the roll against the belt 42 in the vicinityof the raised portions 120 of the roll.

VERNIER BELT TENSIONING SYSTEM

The vernier belt tensioning system 130 represents an inexpensive, highresolution system for obtaining a highly accurate setting of theparallelness of the pulleys 44 and 45. The system is capable ofmaintaining parallelness of the respective pulleys within about ± 0.005to about ± 0.01 inches.

The cone-shaped members 131, which engage the upper run of the belt 42at the front and rear sides thereof, are effective for overcoming minorexcursions of the belt to maintain proper belt tracking. It is stillrequired, however, that the input drive pulley 44 and the idler pulley45 about which the belt 42 is supported, must be sufficiently parallelto avoid major excursions of the belt which would result in catastrophicloss of belt tracking. To insure this high degree of parallelnessbetween the respective belt pulleys 44 and 45, a vernier belt tensioningsystem 130 is employed as shown in FIGS. 8-10.

The driving engagement between the belt 42 and the document is providedby the slack in the belt and the normal force applied through the beltby the input and registration back-up rolls 46 and 47. The normal forceexerted by the belt against the document in the vicinity of the inputand registration back-up rolls 46 and 47 plays a substantial roll inproviding consistent skew-free feeding of the document. This normalforce is controlled as aforenoted by the weight of the rolls andmounting assemblies 110 and 115. The belt 42 tension provides anoff-setting force to the normal force of the rolls 46 and 47 by actingto lift the rolls away from the platen. The higher the belt tension thegreater is the reduction in the effective normal force of the back-uprolls 46 and 47 at the platen. Therefore, it is important to be able toset the belt tension with a high degree of accuracy.

The belt tension is set for the document handling system 11 by means ofthe adjustable side frames 106 and 107 which include a vernier system130 which allows the belt tension to be incremented in small amountswhile maintaining the parallelness of the respective belt pulleys 44 and45.

The drive belt pulley 44 is journaled for rotation in the front and rearside frames 106 and 107 by means of bearings 131. The idler pulley 45 isjournaled for rotation by means of bearings 132 which are slidablysandwiched between the inner 133 and outer 134 vernier plates whichcomprise the adjustable side frames 106 and 107. The bearing 132 ispositioned in a close fitting hole 135 in the outer plate 134 and slideswithin a slot 136 in the inner plate 133. The outer plate 134 is lockedto the inner plate 133 by screws 137 and nuts 138 which are welded tothe inner plate 133. Slots 139 in the outer plates 134 allow them toslide relative to the inner plates 133 for setting belt tension.

The vernier system 130 is comprised of a row of holes 140 spaced anequal distance apart arranged in the respective front and rear outervernier plates 134. A second row of holes 141 spaced an equal distance,which is less than the spacing of the holes in row 140, are arranged ineach of the respective inner vernier plates 133.

The difference in the hole spacings for the holes 140 in the outervernier plates 134 as compared to the holes 141 in the inner vernierplates 133 provides the desired vernier type read-out when the rows ofholes 140 and 141 are overlapped by application of the outer vernierside plates 134 to the inner vernier side plates 135. This difference inthe hole 140 and 141 spacings in the vernier plates 133 and 134 resultsin only a single pair of holes in the respective plates 133 and 134being completely aligned and concentric for any relative position of thevernier plates.

For example, if the difference in spacing for the holes 141 as comparedto the holes 140 is about 0.03 inches then it is possible to adjust thevernier side plates 133 and 134 relative to one another accurately inintervals of 0.03 inches. Similarly, if the difference in the holespacings were 0.01 inches, it would be possible to adjust the vernierside plates 133 and 134 in increments of 0.01 inches. Therefore,relative movement of the vernier side plates 133 and 134 in eitherdirection of the arrow 142 in FIGS. 9 and 10 so that a new set ofoverlapped holes 140 and 141 lines up next adjacent to a previouslyaligned set of holes will result in a 0.03 incremental adjustment for a0.03 inch difference in hole spacing.

The holes 140 in each vernier plate 134 are provided with indicia, asshown, such as numbers or letters. When a desired belt tension isachieved a pin is placed in the aligned vernier holes 140 and 141 of oneside frame 106, for example, hole 0 in FIG. 9. The same holes 140 and141 are aligned at hole 0 in the other side frame 107 and held by a pin.After the side frames 107 and 106 have thus been aligned and the properbelt tension set, the vernier plates 133 and 134 are locked in positionby means of screws 137.

In order to set the belt tension, use is made of the relative movementbetween the document handler cover 150 and the document belt frameassembly 105. The frame assembly 105 is pivoted about the input rolldrive shaft 71, whereas the cover is pivoted about a different hingeaxis 151. This results in relative movement between the transport beltframe assembly 105 and the cover 150 is slidingly secured to the coverby removable straps 152 mounted to bosses 153 on the cover. Tabs 154 onthe side frames 106 and 107 slide on the straps 152 as the frames 105slides down the cover 150 as the cover is raised.

To set the belt tension a fish scale or other suitable tension measuringdevice is secured between one end 155 of the cover 150 and a catch 156which is secured on outer vernier plate 134. The screws 137 are loosenedand the cover 150 is raised until the desired tension is reached, atwhich time note is taken of the vernier hole pair 140 and 141 which arealigned. A pin is then placed in that vernier hole pair. The cover 150is then lowered and the tension measuring device removed. When the coveris raised again, a pin is similarly placed in the same hole pair 140 and141 on the other side of the DHS frame assembly 105. The vernier plates133 and 134 are then locked as aforenoted to maintain the desired belttension and the desired parallinity between the respective belt pulleys44 and 45.

PLATEN REGISTRATION SYSTEM

The purpose of the platen belt transport 40 is to advance the documentonto the platen, and against the platen registration gate 51 so that thedocument can then be scanned by the optical system 18 to provide one ormore copies. Referring to FIGS. 5, 11, and 12, the platen registrationsystem 50 is shown in greater detail. The registration gate 51 comprisesa plate-like member which is comparatively thin and sufficientlyflexible to conform to the beveled edge 160 of the platen P. Theregistration gate 51 is arranged for movement in a plane which isinclined with respect to the plane of the platen P.

In the system which will be described the registration edge 51 isnormally maintained in its retracted position as in FIG. 5. This isdesirable in order to reduce the possibility of operator injury byengagement with the edge of the registration gate 51 when the platencover 150 and document handler is raised off the platen. Theregistration gate 51 is raised into its operative position forregistering a document on the platen as in FIG. 12 only when thedocument is fed onto the platen P. As soon as the document has beenregistered the gate 51 is retracted so that the document can then be fedoff the platen at the end of the copy cycle.

To insure conformity between the gate member 51 and the beveled edge 160of the platen P, a plurality of springs 161, as in FIGS. 5 and 11, arearranged spaced apart across the plate member to bias the gate againstthe platen edge. Four springs 161 are shown. Each is secured to theregistration gate frame 162 and urged against the gate member 51 incantilever fashion. Because of the variability of the springs 161 theforce exerted by each spring is adjustable so that proper conformity canbe maintained between the registration gate 51 and the beveled edge 160of the platen glass P. This adjustment is provided by the mountingscrews 165 which hold the springs to the frame 162. One end 166 of thespring 161 is secured in a slot 167 in the registration gate frame 162and the other end is urged against the gate surface. Tightening thescrew 165 increases the spring pressure and loosening the screw 165reduces the spring pressure. The spring 161 includes a step 168 which iscantilevered to allow the spring force adjustment. These springs 161 areoperative to correct for edge bowing of the gate member 51 and forspring and casting 162 tolerances.

The registration gate 57 is arranged for sliding movement on theregistration gate frame 162. It is urged to its retracted position bymeans of tension springs 170. Screw 171 adjustable stop members 172 areprovided which include projections which pass through slots 173 in theregistration gate 51 to limit its range of travel. Actuation of the gate51 is provided by means of a solenoid 174 which is connected to the gateby means of a pivotally supported link 175. The operative stroke of thesolenoid 174 is adjusted by means of an adjustment screw and wheel 176embedded in the frame 162 which moves the solenoid support frame 177with respect to the register edge frame 162 about pivot screw 178.Screws 179 lock the position of the solenoid frame 177 on the gate frame162.

Referring to FIGS. 5 and 12, the operation of the platen registrationgate is shown in greater detail. In its operative position, as in FIG.5, the register edge 51 engages the belt 42 so as to raise the registerback-up roll 42 off the platen to create a registration "pocket" asshown. This results in a decrease in the normal force of the beltagainst the document as it is advanced into registration against thegate 51. This is desirable since it reduces the occurrence of documentdamage. The document is advanced into engagement with the gate 51 by acoast overdrive of the belt transport 40. This removes any document skewand properly positions the document on the plate P for imaging.

After the document has been properly registered on the platen P, thegate 51 is withdrawn to its retracted position as in FIG. 5. This alsoresults in dropping the register roll 47 back into engagement with thedocument through the belt 42 at a desired normal force which iseffective to advance the document off the platen by actuation of thebelt transport 40. If another document has been pre-registered in thewait station 33, it is fed onto the platen P simultaneously as theprevious document is fed off the platen. If another document is notpre-registered, the first document is fed off the platen P beforeanother document is fed on.

The document which is advanced off the platen P is fed into the nip ofthe output rolls 55. The output rolls 55, as in FIGS. 2, 5, and 7,comprise an upper set of rolls 180 supported about the output roll driveshaft 181. The lower set of idler rolls 182 are mounted on individualshafts S and cantilevered spring 183 biased for engagement with theupper output 180 rolls. The lower idler output rolls 182 include anenlarged diameter central ring 184 which is located between the engagingupper output drive rolls 180. This arrangement serves to corrugate thedocument as it is advanced by the output rolls 55 into the output tray41. This aids in obtaining adequate travel of the document before itengages the other documents in the output tray so that it will properlystack in the output tray.

A guide chute 190 is associated with the output rolls 55. The lowerguide chute 191 is extended by means of a Mylar strip 192 so it flexiblyengages the registration gate cover 193 thereby preventing a sheet frombeing driven downwardly into the registration gate area rather than outthrough the output roll chute 190. The upper chute 194 also includesslidable extension 195 which it adjustably supports. The chute extension195 comprises a plate member which includes a plurality of tabs 196which extend through cooperating slots 197 in the upper chute as in FIG.2. Leaf-type springs 198 are inserted through holes in the tabs 196 andserve to mount the adjustable chute extension 195 to the upper chute 194so that it can be adjusted to provide a desired gap 199 with respect tothe belt 42. This gap 199 preferably is on the order of about 0.03inches so as to reduce the propensity for a document sheet to jam intothe interface between the output rolls 55 and the belt transport 40.

COUNTERBALANCE MECHANISM

While most copying operations will be performed with the documenthandler 11 in its operative position over the platen P, it is alsodesirable for copying books, etc., to be able to manually locatedocuments on the platen. This is accomplished by raising the documenthandler cover 150 to lift the document handler off the platen. Acounterbalance mechanism 200, as in FIGS. 2 and 13, is provided foroffsetting the weight of the document handler 11 and cover 150 to makeit easy to raise or lower them. The counterbalance mechanism 200 iscomprised of a gas spring 201 of the general type which may be obtainedfrom the Gas Spring Corporation, 17 Commerce Drive, Montgomeryville,Pennsylvania, and sold under Part Number 01111-B.

The gas spring cylinder 201 is pivotally secured at one end to a boss204 on the input station frame casting 70. The gas spring piston rod 202is pivotally secured at its free end to a boss 203 on the documentfeeder cover 150. Oil has been added to the gas spring cylinder 201 inorder to provide a damping effect as the cover is raised or lowered. Theoil in the gas spring causes it to act like a dash pot and prevents thecover 150 from falling too fast as it is closed. When the cover is atabout 15° to the horizontal plane of the platen it falls closed sincethere is insufficient force in the gas spring to oppose its closing.

The force necessary to raise the cover 150 and its associated documenthandler 11 is not uniform throughout the range of motion of the cover.For example, as the cover 150 gets more vertical the force of the coverand document handler against the gas spring is markedly reduced. Tocompensate for this reduction in the opposing force of the documentcover 150 and handler 11, a compensating spring 205 is provided which ispivotally secured to the boss 206 on the input casting 70. Thecompensating spring includes a U-shaped hook 207 at its other end whichrides on a pin 208 secured to the boss 203 of the document handler cover150.

As the cover is raised to about 20° to the horizontal the compensatingspring 205 begins to stretch and thereby apply a counter force to thegas spring 201. The amount of this compensating force increases as thedocument feeder cover is raised and the compensating spring 205 expands.This combination of the gas spring 201 and compensating spring 205provides a more correlated force distribution on the cover 150 anddocument handler 11 to prevent a rapid--uncontrolled swing during theopening or closing thereof.

The cover 150 and document handler 11 of this invention are movable fromthe horizontal over a range of motion of from about 0° to about 105°.This means that the cover and document handler move past vertical. Thecounterbalance mechanism 200 provides a unique compound type of actionover that range of motion. A force is applied by the gas spring 201 toinitially lift the platen cover 150. The compensating force of spring205 is then applied at about 20° to counter the force of the gas springas the force exerted by the cover 150 decreases. The amount of thiscompensating force increases as the cover is raised. As the cover passesthe vertical plane the compensating spring 205 acts to balance andcounter the force of the cover which is then increasing.

The counterbalance mechanism 200 is particularly adapted to be employedwithin a confined space. Normally, the document feeder 11 and cover 150,as well as the gas spring 201, and tension spring 205 lie generallyhorizontally. The gas spring 201 is inclined about 5° to 10° to thehorizontal in order to provide the necessary leverage for opening thecover 150. Since the gas spring 201 is inclined generally horizontally,a large force is necessary to lift the cover initially, falling offdrastically as the cover moves between 45° and 105° from the horizontal.

The compound counterbalance mechanism 200 provides a self-closing platencover 150 since the force of the gas spring is inadequate to support theplaten cover at an inclination of less than about 15° to 20° to thehorizontal. The mechanism 200 enables the platen cover 150 and documenthandler 11 to be lifted and held in any desired position over a widerange of orientations.

If desired, the tension spring 205 can be made adjustable to off-settolerance build-ups and optimize the inter-relationship between it andthe gas spring 201. A tension spring adjustment system is not shown inthe drawings, however, it could comprise a turn-buckle interposedbetween the U-shaped hook 207 and the coiled portion of the spring 205.The leg of the U-shaped hook 207 connected to the coiled portion issevered and the resulting ends threaded and connected together by theturn-buckle. In this manner the force exerted by the compensating spring205 could be increased or decreased by adjusting the turn-buckle toincrease or decrease the extension spring.

MANUAL REGISTRATION EDGE

When the document handler 11 is raised to do copying by manual placementof documents on the platen P, the normal document registration edge 51is in its retracted position as described above. Therefore, it isnecessary to provide some means for providing manual registration of adocument on the platen P. This is achieved in accordance with thisdocument handling system 11 by means of a retractable manualregistration edge mechanism 210 as in FIGS. 13 and 14. The manualregistration edge 211 is located at the rear or top edge of the platenP. It comprises a plate-like member 212 which is arranged to slide onand off the platen P. A parallelogram-type linkage is used to providethe sliding movement. A first member 213 is secured to the optical frame214 by screws 215. Two parallel, but spaced apart pivoting links 216 and217 are pivotally secured at one end to the first member 215 and attheir other end to the movable registration member 212. A tension spring218 biases each of the links 216 and 217 toward the extended position oroperative position for the registration member shown in solid lines. Acable 219 is secured to one of the pivoting links 216 at one end and toan actuating member 220 mounted on the document handler cover 150 as inFIG. 13 at its other end.

When the cover 150 is raised as in FIG. 13, the cable 219 is slack sothat the manual registration edge 211 is operatively positioned over theplaten P as in FIG. 14. When the cover is closed as shown in phantom inFIG. 13, the movement of the actuating arm 220 pulls the cable taughtand retracts the manual registration edge 211 to the position shown inphantom in FIG. 14. Therefore, the manual registration edge 211 ispresent over the platen P only when the document feeder cover 150 anddocument feeder 11 are raised off the platen surface. When the documentfeeder cover 150 is in its normal operative position over the platensurface the manual registration edge is retracted. This avoidsinterference between the manual registration edge 211 and the documentsbeing advanced onto the platen by belt transport 40.

DOCUMENT HANDLER DRIVES

The drive motor 230 is connected to the document handler 11 via clutchand pulley 65, timing belts 231 and 232 and intermediate pulleys 233 and234 as shown in FIG. 13. The timing belt 232 is wrapped about theoutboard drive pulley 235 on shaft 71 as in FIG. 2. Timing belts 236 and237 are used to tap the drives input to shaft 71 for connection to thebelt drive pulley 44 and the output drive rollers 180.

OUTPUT TRAY AND DOCUMENT DECELERATOR

Referring now to FIGS. 1, 2, and 15, the document output tray 41 anddocument decelerators 56 features are shown in greater detail. Theoutput tray 41 includes a step or depression 240 at its downstream endwhich serves to collect and appropriately stack small sized documents.If a larger document is copied, it would extend over the lip 241 of thedepression 240 in the tray 41.

A document decelerator support bar 242 is pivotally supported formovement between the positions shown in solid lines and in phantom. Thebar is biased upwardly by torsion spring 247. In the solid line positionthe bar 242 supports two Mylar strips 243 which act to deceleratedocuments exiting from the document handler. The documents pass underthe upper run 244 of the bar 242 and engage the Mylar strips 243 whichact to decelerate and stack the documents in the tray. Improved documentstacking and deceleration is accomplished by means of brush-type pads245 secured to the free ends of the cantilever mounted Mylar strips 243.The brush pads 245 include fibers that are angled with respect to thedirection of document advancement, namely, they are inclined forwardlyand downwardly of the direction of document advancement. As a documentengages the fiber pads 245 it passes easily in the direction in which itis moving because of the inclination of the fibers. However, when thedocument reaches the end face 246 of the output tray 41 and attempts toreverse its direction of movement, the frictional resistance between thefibers of the pads 245 and the document is increased because of theirinclination. The increased frictional resistance causes the documents tostop and stack in a neat pile generally against the end face 246 of theoutput tray 41.

Preferably in accordance with this invention the coefficient of frictionbetween the documents and the fibers of the pads 245 is approximatelyabout 0.2 or less in the direction in which the sheets are advanced intothe output tray 41. In the reverse direction, however, the frictionalforces exerted by the fibers of pads 245 should provide a coefficient offriction greater than about 1.

While any desired material can be employed for the fibrous pads 245, amaterial produced by Collin and Aikman, called "Climber" IF-3961provides excellent results. Alternatively, a Fibertran type material asin the Sanchez, et al. patent could be employed.

The material may be installed as a flat type pad as shown in FIG. 15 oralternatively it could be applied to a roller at the end of a sheetdeflector. Both approaches have been shown to provide successfulresults. An example of a roller at the end of a sheet deflector is foundin U.S. Pat. No. 3,709,492 to Baker, et al. noted in the background ofthis application. The pad shown in the Figures could be easily appliedto that roller surface to give the same result.

The strips 243 preferably are resilient so that their cantilevermounting serves to bias the pads 245 downwardly toward the bottom of thetray. The resiliency or spring-like nature of the strips also providesimproved damping and deceleration of the document as compared to a rigidmember.

If it is desired to do book copying, the decelerator support bar 242 isin the way. However, it can be deflected downwardly by the book itself,as shown in phantom, so that a book can be easily laid over it and theplaten P. The registration gate assembly 50 has been inclined withrespect to the plane of the platen P as described above. Thisorientation provides an ideal book registration edge, so that it is notnecessary to break the binding of a book as it is placed on the platenfor copying. Deflection of the bar 24 allows the book to be easilyplaced over the platen without interference with the bar.

The operator work space can be increased, if desired, by providing adocument holding tray 250 which is pivotally supported about the upperrun 244 of the bar 242 as shown in phantom in FIG. 15. In the positionshown, the tray 250 is held in a cantilevered arrangement by a pin 251projecting from the upper run 244 of the bar. To gain access to thedocument output tray in the document handling mode of operation the tray250 is pivoted upwardly about the upper run 244 of the bar. For bookcopying, the book is merely laid against the platen and as it interceptsthe tray 250 and bar 244, they are automatically urged downwardly toprovide the desired book copying arrangement as shown.

The torsion spring 247 must, of course, be sufficiently strong tocounterbalance the weight of the bar 242 when used alone as well as anyadditional weight supported by the bar such as the tray 250. However,the spring force must not be so strong so as to require considerableeffort to move the bar 242 and tray 250 to their retracted position forbook copying. If desired, in accordance with this invention a switch canbe arranged to sense downwardly deflection of the bar 242. Upon sensingsuch deflection a solenoid or other type actuating device would move thebar to its fully retracted position in response to the urging of thebook. Such an auxiliary powered assist to retraction would be necessaryonly in the event that the spring force of spring 247 required tocounterbalance the weight supported by the support member 242 was solarge that the ordinary weight of a book would be inadequate to fullyretract the support bar or member.

The control system for operating the document handling system describedabove does not form a part of the present invention and any desiredsystem could be employed as are known in the prior art.

The patents, applications, and texts referred to specifically in thisapplication are intended to be incorporated by reference into theapplication.

It is apparent that there has been provided in accordance with thisinvention a retractable support member which fully satisfies theobjects, means and advantages set forth hereinbefore. While theinvention has been described in conjunction with specific embodimentsthereof, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art in light of theforegoing description. Accordingly, it is intended to embrace all suchalternatives, modifications and variations as fall within the spirit andbroad scope of the appended claims.

What is claimed is:
 1. In a reproducing apparatus including anilluminating station and means for forming an image on a sheet ofsupport material of an object positioned at said illuminating station,said illuminating station including a transparent viewing platen havinga registration edge against which said object is placed for imaging, acatch tray arranged adjacent said registration edge of said platen, aretractable support member arranged adjacent said registration edge ofsaid platen and above said catch tray, document decelerating meanssupported by said retractable support member, means for supporting saidsupport member in a first position above the level of said platenwhereby said document decelerating means is positioned for deceleratingdocuments as they may be advanced into said catch tray and forretracting said support member to a second position downwardly of saidfirst position in response to the urging of an object placed on saidviewing platen.
 2. An apparatus as in claim 1, further including adocument feeding means for discharging a document from said platen intosaid catch tray.
 3. An apparatus as in claim 1, further including asheet supporting tray supported by said support member whereby both saidsupport member and said tray can move downwardly in response to theurging of an object placed on said viewing platen.
 4. An apparatus as inclaim 2, further including a supporting tray supported by said supportmember whereby both said support member and said tray can movedownwardly in response to the urging of an object placed on said viewingplaten.
 5. An apparatus as in claim 4, wherein said document feedingmeans comprises a belt-type transport.
 6. An apparatus as in claim 3,wherein said support member comprises a U-shaped member, and whereinsaid support member support means comprises means for pivotallysupporting the free ends of said support member, and resilient means forholding said support member in said first position when it is not urgedto said second position by an object placed on said viewing platen. 7.An apparatus as in claim 6, wherein said resilient means comprises atleast one torsion spring.
 8. An apparatus as in claim 3, wherein saidsheet holding tray is pivotally supported about said support member andfurther including stop means supported by said support member forholding said tray in an operative position.
 9. An apparatus as in claim7, wherein said image forming means comprises a photosensitive surfacearranged for movement; means for forming an electrostatic image of saidobject at said platen on said photosensitive surface; means fordeveloping said electrostatic image to render it visible; and means fortransferring said visible image to said support sheet.